The present invention relates generally to gravure printing and more particularly to the application of gravure printing plates to gravure printing drums.
Gravure printing plates are well known in the art, An example of a gravure plate is disclosed in European Patent application No. EPO. 928685 assigned to the CreoScitex Corporation Ltd. The gravure plate usually includes a substrate layer, a wash-off layer, a protective layer and an IR ablatable layer. Imaging of a gravure plate so as to create an image representing the information to be printed typically includes the following steps:
1. Exposing the protective layer to IR radiation. This step may be done, for example, by LOTEM-FLEX 40-45 manufactured by CreoScitex Corp. Ltd. of Herzlia, Israel.
2. Exposing the wash-off layer to UV radiation; and
3. Washing off the uncured wash-off layer by a solvent.
Once the process described above is completed, the gravure plate is ready to be used as a printing plate. In the printing set-up the gravure plate is attached to the drum of the gravure printing press for printing. The printing process includes application of ink to the outer surface of the gravure plate: the voids produced during the imaging process described above are filled with ink, while the surplus ink is wiped off by a closely contacting wiper, commonly known as the xe2x80x9cdoctor bladexe2x80x9d.
Because of the wiping action of the xe2x80x9cdoctor bladexe2x80x9d, the outer surface of the gravure plate must be smooth, without gaps, or seams between the butted edges, or overlap of the edges, since these may show up in the print or may catch the blade and thus peel off the printing plate.
Many mechanisms for clamping gravure plates on printing drums are known in the art, most of them based on complex mechanisms. One such mechanism is disclosed in U.S. Pat. No. 4527478.
The present invention relates to the application of gravure plates to drums of gravure printing machines, using double-sided adhesive foil. The application of the plate to the drum is done in two stages: in the first stage, the double-sided foil is applied and cut, so as to butt the two edges accurately. In the second stage, the gravure plate is applied and its edges are cut so as to butt the edges, leaving practically no gap.